A $3.3 trillion industry must change drastically if we want to save Earth

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If the world is going to fight climate change, it's not just fossil fuels we need to worry about.

According to a new study, we'll have to get very clever about our food supply.

In a study published Tuesday in the journal Global Change Biology, scientists suggest that greenhouse gases emitted by global agriculture will have to be cut — and drastically, perhaps five times as much as current reductions call for.

This marks the first calculation of precisely how much the agricultural sector will need to reduce its output of potent heat-trapping gases like methane (which is far worse than carbon dioxide) in order to satisfy the Paris Agreement on climate change.

That agreement — signed by 175 countries, including the US — stipulates that nations must work together to not exceed a 2-degree Celsius (3.6-degree Fahrenheit) increase in global temperatures by the year 2100.

Carbon dioxide is the largest greenhouse-gas contributor to our current global warming. It's the culprit most officials and activists talk about, but it's not the whole story.

"The research is a reality check," University of Vermont ecologist and study co-author Lini Wollenberg said in a press release. She noted that that without innovations in agricultural practices, our efforts "won't make a dent" in our emissions future.

Wollenberg and her team studied greenhouse gases that stem from agriculture as well as natural sources. One was methane, which traps heat about 25 times better than carbon dioxide, and livestock like cows and pigs emit heavily as a result of digestive processes and manure storage methods. The team also looked a nitrous oxide — a whopping 200 to 300 times more potent than CO₂ and also generated by agriculture.

Wollenberg and her colleagues found that, given today's rate agricultural growth, current plans will cut potent non-carbon dioxide emissions by only 21% to 40% of what's required in order to keep global warming under 2 deg C.

Put another way, the $3.3 trillion global agriculture industry must find a way to cut more than twice as much methane, nitrous oxide, and other emissions.

"Mitigating those emissions represent a potential to mitigate more quickly," study co-author and agroecologist Meryl Richards told Tech Insider.

Agriculture contributes 56% of the world's nitrous oxide and methane emissions, according to Richards.

So, keeping those gases out of the atmosphere could do a lot to slow the pace of warming.

"The atmospheric concentrations that we're seeing [of methane and nitrous oxide] are unprecedented on the planet in the last 800,000 years," she says. "The quantity of these greenhouse gases that are in the atmosphere vastly exceeded what could be contributed by natural causes."

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